Display panel having rows and columns of cells with wide viewing angle

ABSTRACT

The display panel comprises first and second layers of communicating gas-filled display cells. The first layer includes a first plate having slots or grooves, with first electrodes seated in the grooves, and second electrodes supported by the plate so that the first and second electrodes and the gas in the slots between them form a first layer of cells. An apertured center cell sheet having rows and columns of apertures or cells is seated on the second electrodes. The apertured center cell sheet includes deep longitudinal slots which extend down from the top surface thereof, and a thin rib at the base of each slot includes the cell apertures. Third electrodes are disposed between the apertured cell sheet and the panel face plate. The second and third electrodes and the gas-filled space between them comprise the second layer of cells.

United States Patent [191 Maloney et a1.

[451 Nov. 19, 1974 DISPLAY PANEL HAVING ROWS AND COLUMNS OF CELLS WITH WIDE VIEWING ANGLE Inventors: Thomas C. Maloney, Bernardsville;

Donald E. Miller, Asbury, both of NJ.

Burroughs Corporation, Detroit, Mich.

Filed: June 28, 1973 App]. No.: 374,398

Assignee:

References Cited UNITED STATES PATENTS Primary ExaminerArchie R. Borchelt Assistant Examiner-Wm. H. Punter Attorney, Agent, or Firm-Robert A. Green; Edward G. Fiorito; Paul W. Fish [5 7] ABSTRACT The display panel comprises first and second layers of communicating gas-filled display cells. The first layer includes a first plate having slots or grooves, with first electrodes seated in the grooves, and second electrodes supported by the plate so that the first and second electrodes and the gas in the slots between them form a first layer of cells. An apertured center cell sheet having rows and columns of apertures or cells is seated on the second electrodes. The apertured center cell sheet includes deep longitudinal slots which extend down from the top surface thereof, and a thin rib at the base of each slot includes the cell apertures. Third electrodes are disposed between the apertured cell sheet and the panel face plate. The second and third electrodes and the gas-filled space between them comprise the second layer of cells.

11 Claims, 6 Drawing Figures DISPLAY PANEL HAVING ROWS AND COLUMNS OF CELLS WITH WIDE VIEWING ANGLE BACKGROUND OF THE INVENTION One type of display panel presently available commercially is known as a SELF-SCAN panel. This type of panel includes a base plate, an apertured center sheet, and a cover plate, and associated arrays of electrodes which form first and second layers of cells. The cells are arrayed in rows and columns. The cells in the first layer are operated as scanning cells, and the cells in the second layer are operated as display cells to display a message or character or the like. These devices are commercially successful devices; however, the apertured center sheet, whose apertures comprise the display cells, has a certain thickness which, it can be seen, determines the maximum angle at which the display can be viewed comfortably.

In addition, the cell depth provides a limiting influence on the light output from each cell, and it has been customary to provide cell walls which .are lightreflecting in order to increase the light output. This, however, decreases the contrast between the glowing gas and the cell wall.

SUMMARY OF THE INVENTION The present invention provides greater contrast and light output and greater viewing angle than SELF- SCAN panels of the past, and, briefly, these results are achieved by reducing the effective height of the walls of the display cells. As a result of this improvement in structure, increased light output and greater contrast are achieved without specially treating the walls of the cells.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective exploded view of a display panel embodying the invention;

FIG. 2 is a sectional view, taken along lines 22 of FIG. 1, but showing the display panel assembled, rather than in exploded view;

FIG. 3 is a sectional view along lines 33 of FIG. 1 showing the panel assembled;

FIG. 4 is a perspective view, partly in section, of a portion of a display panel embodying the invention;

FIG. 5 is an enlarged sectional view of a panel cell of the prior art; and

FIG. 6 is an enlarged sectional view of a panel cell embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 3, a display panel 10 embodying the invention includes a first insulating plate of glass, ceramic, or the like having top surface 40 and bottom surface 50 and having a plurality of parallel slots or channels formed in the top surface 40 thereof. The number of slots is determined by the number and size of the characters to be displayed in the panel, as will be clear to those skilled in the art.

First electrodes 60, generally operated as scanning anodes, are seated at the bases of the slots or grooves 30. The electrodes 60 may be wires, flat strips of metal, or they may be plated or evaporated or otherwise formed in the slots.

The panel 10 also includes second electrodes 70, normally operated as scanning cathodes, seated on or in (as shown) the top surface 40 of the first plate 20. The second electrodes 70 are also parallel to each other, and they are oriented, at an angle, preferably 90, to the first electrodes 60. The electrodes 70 are preferably flat metal strips. The region at which each second electrode 70 crosses a first electrode 60 defines a scanning gas cell 90, and each electrode 70 has an aperture 100 at this region so that communication can take place from each scanning cell 90 through electrode 70 to other elements disposed above the electrodes 70 (to be described). The cathodes 70 are each aligned with a column of scanning cells 90.

A second insulating plate I10 having a plurality of apertures or cells 120, used as display cells and arrayed in rows and columns, is seated on the electrodes 70, with each aperture or cell 120 aligned with an aperture and with ascanning cell 90. The plate may be of glass, ceramic, or the like, treated so that it does not reflect light. Thus, the plate is made black in color in a preferred embodiment of the invention.

The panel 10 is completed by an assembly including electrodes 130, preferably wires, and a cover or face plate 150 which is seated on center sheet 110 with the electrodes 130 between them. The electrodes 130 are normally operated as display anodes, and they are disposed parallel to scanning anodes 60 and perpendicular to cathodes 70. Each electrode 130 is aligned with a row of display cells 120, and each display cell is made up of a portion of an anode 130, a portion of a cathode 70 and the gas between them.

According to the invention, the center sheet 110 is provided with a plurality of deep slots 112, each of which extends along a row of cells 120. Thus, the actual holes or cells are formed in a thin rib 114 at the base of each slot. The longitudinal ribs or walls 1 16 between the slots 112 determine the height or thickness of sheet 110 and thus the spacing of the electrodes from cathodes 70. The longitudinal ribs 116 have a top surface 140, and the sheet 110 has a bottom surface 142. In addition, each hole or cell 120 is positioned between and is defined by a cross rib or a wall 118 which may have a rectangular cross-section, as shown in FIG. 3, but preferably has a generally triangular crosssection, as shown in FIG. 4, to improve the angle at which a viewer can see the portion of cathode 70 disposed beneath each cell.

It is noted that electrodes 130 may be transparent conductive films fonned on the bottom surface of face plate 150. In one construction, the electrodes 130 are wires, and their ends are secured to the bottom surface of the face plate in any suitable manner, for example, by means of a glass frit cement.

In panel 10, the plates 20, 110, and are sealed together at their edges by means of a glass fn't or the like to form a seal 170, shown in FIGS. 2 and 3. For convenience in making this seal, top plate 150 and bottom plate 20 are usually made somewhat larger than center plate 110, as shown.

Panel 10 also includes an ionizable gas such as argon, neon, or the like, preferably a Penning mixture of such gases, and including a small quantity of mercury to minimize cathode sputtering, all at a suitable pressure for the intended purpose. The gas may be introduced by means of a tubulation (not shown) suitably secured to the panel, or it may be introduced in any other suitable manner. The gas is provided at a relatively high pressure in the range of about 200 to 250 mm Hg to obtain favorably high light output. However, it is well known that other pressures could be used.

The operation of a display panel such as panel 10 is described in detail in copending application Ser. No. 255,133, filed May 19, I972. Briefly, in operation of the panel, the columns of scanning cells are turned on sequentially by applying operating potential to all of the scanning anodes simultaneously and then applying operating potential to each of the scanning cathodes in turn.

Simultaneously with this scanning operation, and synchronously with the scanning rate, information signals are applied to the anode electrodes 130, and, where ON signals are present, glow is transferred upwardly into cells 120, at an intensity determined by the level of the ON signals, to display a visible message. As each column of cells is scanned in turn, and information signals are applied, a stationary but changeable display is distributed to the columns of cells 120 and is visible through the top plate. The glow present in the lower cells 90, however, is masked for the most part by the panel structure and is not visible through the top plate, so that the internal scanning operation characteristic of the panel does not interfere with the display.

The advantages of the invention can be seen when the prior art display cell structure illustrated in FIG. 5 is compared with the structure of the invention, as illustrated in FIG. 6. It is clear, referring to FIG. 5, that a viewer V looking at the panel from an angle does not see cathode glow G directly, but the bulk of the light he receives is reflected from the walls of the cells. It can be shown mathematically, and it is well known to those skilled in the art, that the total area of light generated at the cathode does not reach the viewer. However, referring to FIG. 6 and a representation of a cell embodying the invention, it is evident that a viewer V positioned at an angle, and at a wide angle, sees substantially all of the cathode glow itself. It can be clearly seen that the viewing angle is thus considerably greater in this case.

In addition, as noted above, in order to increase the light reflection from cells such as the cell shown in FIG. 5, the walls are coated with a white or other lightreflecting substance C so that the contrast between the glow and the color of the cell walls is reduced. In cells of the type shown in FIG. 6, the cell walls can be black or otherwise non-reflecting, and maximum contrast be tween the cathode glow and the cell walls is achieved. This permits a panel embodying the invention to be operated in higher ambient light than prior art panels.

What is claimed is:

l. A display panel comprising a first insulating plate having a top surface and a bottom surface and having a plurality of first parallel grooves in said top surface,

a first anode electrode in each said first groove,

a plurality of second parallel cathode electrodes spaced from said first electrodes and oriented at an angle to said first electrodes so that each second electrode crosses a plurality of first electrodes,

each crossing of a first electrode and a second electrode spaced therefrom defining a gas volume which comprises a first gas cell,

a second plate having top and bottom surfaces and positioned above and in sandwich relation with said first plate,

a plurality. of second parallel grooves formed in said top surface of said second plate and extending downwardly therein to close to said bottom surface thereof, each of said second grooves being generally vertically aligned with one of said first grooves in said first plate,

a plurality of cross ribs disposed in each of said second grooves,

said cross ribs being spaced apart along each of said second grooves with a portion of a cathode disposed in the space between each pair of cross ribs,

said cross ribs extending from near the bottom surface of said second plate toward the top surface thereof,

said cross ribs being of a thickness which is considerably less than the thickness of said second plate,

the space between adjacent pairs of said cross ribs defining apertures which are operated as second cells and each of which is aligned with a first cell,

third electrodes positioned on the top surface of said second plate, each aligned with a group of said apertures whereby a portion of each third electrode is aligned with a portion of a second electrode and a portion of a first electrode at each said aperture, and

a top glass viewing plate covering said third electrodes, said first plate, second plate, and viewing plate being sealed together with an ionizable gas included inside said panel and in said cells,

said thin cross ribs providing isolation between said adjacent cathodes while permitting a viewer looking through said viewing window along each of said slots to see all of said cathode electrodes aligned with said display cells even when said viewer views said panel over a relatively wide viewing angle.

2. The panel defined in claim 1 wherein said cross ribs have a rectangular cross-section.

3. The panel defined in claim 1 wherein said cross ribs have a generally triangular cross-section.

4. The panel defined in claim 1 wherein the greater portion of each said second electrode is exposed in the aperture between adjacent cross ribs.

5. The panel defined in claim 1 wherein said second electrodes comprise metal strips which extend along columns of said first and second cells, each of said strips having a generally rectangular cross-section and having generally parallel edges,

each cross rib in a groove being seated on adjacent second electrodes in contact with the edge portions thereof so that the greater portion of the associated portion of a second electrode is exposed between adjacent cross ribs.

6. The panel defined in claim 1 wherein said first electrodes and said third electrodes are elongated and are oriented generally in the same directions, said second electrodes being elongated and oriented perpendicular to said first and third electrodes.

7. The panel defined in claim 1 wherein said first and third electrodes are elongated wires and said second electrodes are elongated flat strips.

8. The panel defined in claim 1 wherein said first and third electrodes are elongated wires and said second electrodes are elongated flat strips which have apertures at each region where a second electrode crosses a first electrode.

9. The panel defined in claim 1 wherein said first electrodes are seated in said grooves and said second electrodes are seated on the top surface of said first plate.

10. A display panel comprising a gas-filled envelope having a viewing window and including i a first insulating plate having a top surface and a bottom surface and having a plurality of parallel first grooves in said top surface,

a first anode electrode in each said first groove,

a plurality of second parallel cathode electrodes spaced from said first electrodes and oriented at an angle to said first electrodes so that each second electrode crosses a plurality of first electrodes,

each crossing of a first anode electrode and a second cathode electrode spaced therefrom defining a gas volume which comprises a first gas cell,

a second insulating plate having top and bottom surfaces and seated on said second cathode electrode, said second plate having a plurality of apertures arrayed in rows and columns, with each aperture comprising a second gas cell and aligned with and exposing a portion of a cathode electrode,

said second plate having a plurality of second grooves formed in its top surface and extending downwardly to close to said bottom surface, said second grooves being oriented transverse to said cathode electrodes and being defined by longitudinal walls having substantially the same thickness as said second plate, there being a series of said apertures spaced apart at the base of each of said second grooves, said apertures being spaced apart by a thin cross rib which extends between adjacent ones of said longitudinal walls, said cross ribs having a height which is considerably less than the height of said longitudinal walls,

said cross ribs permitting said cathodes exposed in each of said second grooves to be visible to a viewer looking through said viewing window over a relatively wide viewing angle. 11. A display panel comprising a gas-filled envelope including an array of scanning cells disposed in rows and columns, first and second electrode means associated with said scanning cells for energizing said cells column-bycolumn, said first electrode means comprising a plurality of cathode electrode strips adapted to exhibit cathode glow and disposed parallel to each other spaced apart in a common plane, an insulating plate seated on said cathode electrodes and having a top surface and a bottom surface, an array of display cells formed in said plate and disposed in rows and columns, each column of said display cells being aligned with one of said cathode electrodes and the display cells in each row, each being aligned with a separate cathode electrode, a plurality of slots formed in said insulating plate and oriented transverse to said cathode electrodes and aligned with the rows of said display cells, said slots being of such depth that only thin insulating ribs remain within said slots, each such rib being positioned between two adjacent cathode electrodes and between two adjacent display cells so that a portion of a cathode electrode is exposed between two adjacent ones of said ribs, and a face plate viewing window over said insulating plate and forming a portion of said envelope, said thin cross ribs providing isolation between adjacent cathodes while permitting a viewer looking through said viewing window along each of said slots to see all of said cathode electrodes aligned with said display cells even when said viewer views said panel over a relatively wide viewing angle. 

1. A display panel comprising a first insulating plate having a top surface and a bottom surface and having a plurality of first parallel grooves in said top surface, a first anode electrode in each said first groove, a plurality of second parallel cathode electrodes spaced from said first electrodes and oriented at an angle to said first electrodes so that each second electrode crosses a plurality of first electrodes, each crossing of a first electrode and a second electrode spaced therefrom defining a gas volume which comprises a first gas cell, a second plate having top and bottom surfaces and positioned above and in sandwich relation with said first plate, a plurality of second parallel grooves formed in said top surface of said second plate and extending downwardly therein to close to said bottom surface thereof, each of said second grooves being generally vertically aligned with one of said first grooves in said first plate, a plurality of cross ribs disposed in each of said second grooves, said cross ribs being spaced apart along each of said second grooves with a portion of a cathode disposed in the space between each pair of cross ribs, said cross ribs extending from near the bottom surface of said second plate toward the top surfaCe thereof, said cross ribs being of a thickness which is considerably less than the thickness of said second plate, the space between adjacent pairs of said cross ribs defining apertures which are operated as second cells and each of which is aligned with a first cell, third electrodes positioned on the top surface of said second plate, each aligned with a group of said apertures whereby a portion of each third electrode is aligned with a portion of a second electrode and a portion of a first electrode at each said aperture, and a top glass viewing plate covering said third electrodes, said first plate, second plate, and viewing plate being sealed together with an ionizable gas included inside said panel and in said cells, said thin cross ribs providing isolation between said adjacent cathodes while permitting a viewer looking through said viewing window along each of said slots to see all of said cathode electrodes aligned with said display cells even when said viewer views said panel over a relatively wide viewing angle.
 2. The panel defined in claim 1 wherein said cross ribs have a rectangular cross-section.
 3. The panel defined in claim 1 wherein said cross ribs have a generally triangular cross-section.
 4. The panel defined in claim 1 wherein the greater portion of each said second electrode is exposed in the aperture between adjacent cross ribs.
 5. The panel defined in claim 1 wherein said second electrodes comprise metal strips which extend along columns of said first and second cells, each of said strips having a generally rectangular cross-section and having generally parallel edges, each cross rib in a groove being seated on adjacent second electrodes in contact with the edge portions thereof so that the greater portion of the associated portion of a second electrode is exposed between adjacent cross ribs.
 6. The panel defined in claim 1 wherein said first electrodes and said third electrodes are elongated and are oriented generally in the same directions, said second electrodes being elongated and oriented perpendicular to said first and third electrodes.
 7. The panel defined in claim 1 wherein said first and third electrodes are elongated wires and said second electrodes are elongated flat strips.
 8. The panel defined in claim 1 wherein said first and third electrodes are elongated wires and said second electrodes are elongated flat strips which have apertures at each region where a second electrode crosses a first electrode.
 9. The panel defined in claim 1 wherein said first electrodes are seated in said grooves and said second electrodes are seated on the top surface of said first plate.
 10. A display panel comprising a gas-filled envelope having a viewing window and including a first insulating plate having a top surface and a bottom surface and having a plurality of parallel first grooves in said top surface, a first anode electrode in each said first groove, a plurality of second parallel cathode electrodes spaced from said first electrodes and oriented at an angle to said first electrodes so that each second electrode crosses a plurality of first electrodes, each crossing of a first anode electrode and a second cathode electrode spaced therefrom defining a gas volume which comprises a first gas cell, a second insulating plate having top and bottom surfaces and seated on said second cathode electrode, said second plate having a plurality of apertures arrayed in rows and columns, with each aperture comprising a second gas cell and aligned with and exposing a portion of a cathode electrode, said second plate having a plurality of second grooves formed in its top surface and extending downwardly to close to said bottom surface, said second grooves being oriented transverse to said cathode electrodes and being defined by longitudinal walls having substantially the same thickness as said second plate, there being a series of said apertures spaced apart at the base of each of said second grooves, said apertures being spaced apart by a thin cross rib which extends between adjacent ones of said longitudinal walls, said cross ribs having a height which is considerably less than the height of said longitudinal walls, said cross ribs permitting said cathodes exposed in each of said second grooves to be visible to a viewer looking through said viewing window over a relatively wide viewing angle.
 11. A display panel comprising a gas-filled envelope including an array of scanning cells disposed in rows and columns, first and second electrode means associated with said scanning cells for energizing said cells column-by-column, said first electrode means comprising a plurality of cathode electrode strips adapted to exhibit cathode glow and disposed parallel to each other spaced apart in a common plane, an insulating plate seated on said cathode electrodes and having a top surface and a bottom surface, an array of display cells formed in said plate and disposed in rows and columns, each column of said display cells being aligned with one of said cathode electrodes and the display cells in each row, each being aligned with a separate cathode electrode, a plurality of slots formed in said insulating plate and oriented transverse to said cathode electrodes and aligned with the rows of said display cells, said slots being of such depth that only thin insulating ribs remain within said slots, each such rib being positioned between two adjacent cathode electrodes and between two adjacent display cells so that a portion of a cathode electrode is exposed between two adjacent ones of said ribs, and a face plate viewing window over said insulating plate and forming a portion of said envelope, said thin cross ribs providing isolation between adjacent cathodes while permitting a viewer looking through said viewing window along each of said slots to see all of said cathode electrodes aligned with said display cells even when said viewer views said panel over a relatively wide viewing angle. 